Submitted by Nathália Faria da Silva (nathaliafsilva.ufv@gmail.com) on 2017-06-23T19:45:48Z No. of bitstreams: 1 texto completo.pdf: 290821 bytes, checksum: 6d94f08285f881eaf94010cf719ebcde (MD5) / Made available in DSpace on 2017-06-23T19:45:48Z (GMT). No. of bitstreams: 1 texto completo.pdf: 290821 bytes, checksum: 6d94f08285f881eaf94010cf719ebcde (MD5) Previous issue date: 2004-08-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Os objetivos deste trabalho foram determinar as taxas de recuperação de Fe e de Mn pelos extratores Mehlich-1, Mehlich-3 e DTPA; e modelar as variações dessas taxas em relação às características ligadas à capacidade tampão do solo. Foram realizados dois experimentos na Universidade Federal de Viçosa, utilizando 15 solos, seis dos quais foram estudados na ausência e presença de calagem e cada um recebeu seis doses dos micronutrientes Fe ou Mn, sendo que cada micronutriente foi considerado em um experimento diferente. Os experimentos foram montados simultaneamente, em delineamento em blocos casualizados, com três repetições. A extração foi feita com os métodos Mehlich-1, Mehlich-3 e DTPA e a dosagem por espectrofotometria de absorção atômica. Os teores de Fe e Mn recuperados pelo Mehlich-1, Mehlich-3 e DTPA aumentaram com o aumento das doses aplicadas desses nutrientes aos solos, sem ou com calagem. A capacidade de extração do Fe dos solos seguiu, nas médias dos solos, a seguinte ordem: Mehlich-1 > Mehlich-3 > DTPA, enquanto a capacidade de extração do Mn dos solos foi, nas médias dos solos: Mehlich-3 > Mehlich-1 > DTPA. Os teores obtidos pelos extratores Mehlich- 3 e DTPA foram os que mais variaram em relação à capacidade tampão do solo. Nos solos com calagem foram obtidas menores taxas de recuperação do Fe e do Mn. As taxas de recuperação de Fe e Mn dos solos pelos extratores usados estão relacionadas com os teores de matéria orgânica, de argila e com o equivalente de umidade. Apesar dos teores diferentes de Fe disponível, os extratores Mehlich-1, Mehlich-3 e DTPA estão altamente correlacionados uns com os outros, sugerindo uma capacidade preditiva semelhante com relação ao Fe disponível. No caso do Mn, somente existe correlação entre Mehlich-1 e DTPA nos solos sem calagem e entre Mehlich-3 e DTPA nos solos com calagem. / The increase of the demand for micronutrients in agriculture and the concern with the environmental impacts of the agricultural activity on the soil has been raising growing interest in the last years. The objectives of this work were to determine the recovery rates of Fe and Mn by the extractors Mehlich-1, Mehlich-3 and DTPA; and to model the variations of those rates in relation to the characteristics linked to the buffer capacity of the soil. Two experiments were set up at the Federal University of Viçosa, using 15 soils, six of which were studied in the presence and in the absence of liming and each one received six doses of the micronutrientes Fe or Mn, each micronutrient being considered in a different experiment. The experiments were simultaneously set in a randomized block design, with three replicates. The extraction was made with the methods Mehlich-1, Mehlich-3 and DTPA and the dosage by atomic absorption spectrophotometry. The contents of Fe and Mn recovered by Mehlich-1, Mehlich-3 and DTPA increased lineally with the increase of the applied doses of those nutrients to the soils, independently of liming. The soil Fe extraction capacity proceeded, on average, the following order: Mehlich-1> Mehlich-3> DTPA, while the soil Mn extraction capacity was, on average: Mehlich-3> Mehlich-1> DTPA. The contents obtained by the extractors Mehlich-3 and DTPA were the ones that varied most in relation to the ixsoils buffer capacity. In the soils with liming, smaller recovery rates of Fe and Mn were obtained. The recovery rates of soil Fe and Mn by the extractors are related with the contents of organic matter, clay and with the moisture equivalent. In spite of the different amounts of available Fe in the soils, the extractors Mehlich-1, Mehlich-3 and DTPA are highly correlated among them, suggesting a similar predictive capacity if it is considered the available Fe. In the case of Mn, correlation only exists between Mehlich-1 and DTPA in the soils without liming and among Mehlich-3 and DTPA in the soils with liming.